Drier for photographic prints and the like



LYNN

DRIER FOR PHOTOGRAPHIC PRINTS AND THE LIKE v @v A Filezd Oct. 11., 193?INVENTOR. m aberf f Cy/7.

BY I

ATTORNEY.

ate nte d July 4, 19 39 UNITED STATES PATENT OFFICE DRIER FORPHOTOGBAPHIC PRINTS AND THE LIKE 3 Claims.

My invention relates to equipment for drying Jhotographic prints and thelike.

It is customary in drying glossy photographic prints to lay the printsface down on a smooth surface, generally a plate provided for thispurpose and called a squeegee tin which consists of a rectangular sheetof metal Which has been chromium plated or enameled on one side. The

prints are simply spread out on the squeegee tin without anything tohold them down flat against its surface or to prevent them from blowingaway. Dull prints are generally dried by placing them face up on thesqueegee tin or other surface. As a result of these drying methods, theprints curl and dry non-uniformly, causing specks and spots to appearand requiring the prints toibe straightened after drying. Instraightening th'prints they are often broken because of the brittlenessof some overdried surface portion. Besides these dimculties, theordinary procje'ss is slow and cumbersome.

It is an-'objectof my invention to provide a drier for prints which isconvenient and fast in operation, and which results in uniform drying ofthe prints without curling, specking or spot-. ting.

Another object is to provide a drier which makes it possible to' leavein the print a desired amount of moisture so that the print remainsflexible and is not easily cracked.

Another object is to provide a drier which is suitable for drying printsof either dull or glossy finish.

Another object of my invention is to provide a drier that presses theprints tightly between two surfaces while they are being dried.

A further object is to provide a drier in which the heat is uniform overthe drying surface and is adjustable and may be held constant at thedesired temperature.

Still another object is to provide a drier which employs for a smoothsurface thecommon squeegee tin, making it unnecessary to resurface anypermanent part of the equipment after long use. The squeegee tin issimply discarded when worn out and another substituted for it.

These objects are attained in a manner which will be clear from aconsideration of the following description taken in connection with theaccompanying drawing, of which:

Fig. 1 is an elevational view of my drier with the fabric surface andits tightening frame in the operating position.

Fig. 2 is an elevational view of my drier with the fabric and its"tightening frame in the raised position in which it stands while loadingand unloading prints.

Fig. 3 is a plan view of the dried with the fabric and its tighteningframe in the operating position, showng much of the internalconstruction in dotted lines.

Fig. 4 is an elevational view in section of the drier taken along theline 4-4 of Fig. 3 in the direction of the arrows as shown.

My drier has a main frame constructed with end plates H1 and H,preferably of cast metal to which are attached side members of sheetmetal 12 and l3 and a sheet metal bottom It. A convex sheet metal cover15, preferably formed in the shape of a portion of a cylindrical surfacewith its axis parallel to a longitudinal edge of the frame, rests on theframe and covers the entire top of it. The end plates l and II haveextending lugs l6 and II respectively which are bored to receive a rodl8 which passes therethrough. Pivoting on the rod l8 is a tighteningframe comprising arcuate members is and 20 which are joined by a rod 2iat the back and by other rods 22 and 23 at the front. Encircling rod l8at one end and rod 23 at the other is a heavy pre-shrunk absorbentfabric 24 made from Egyptian long fibre cotton and which is adapted tooverlie the metal sheet l and permit the rod 23 to be brought below theadjacent edge of the drying surface to be latched in that position bymeans of the mechanism 25 provided. The members l9 and end at the frontin handles 26 and 21 for convenience in raising'and lowering the fabricand its tightening frame. The latching mechanism comprises at both sidesof the drier ratchets 28 with buttress shaped teeth attachedstationarily to the drier frame and pawls 29 pivoted about the rod 23and adapted to engage the ratchets 28 when the tightening frame islowered to stretch the fabric 24 tightly over the drying surface. Afterengagement with the ratchets, pawls 29 are held from rotating by comingto a stop against the rod 22.

To release the latch, the extending ends of the pawls are depressed withthe thumbs while pressure is applied downward to members l9 and 20.Spiral springs on the rod 23 which are attached to the pawls and to theadjacent members of the tightening frame maintain the pawls in positionto engage the ratchets.

Within the main frame and supported thereby in a spaced relation to thecover I5 is a plate of metal 30 which together with the side and endwalls of the frame and the cover l5 definea compartment within which islocated electrical heating units which are adapted to provide heat forthe cover I5. The electrical heater is preferably constructed asfollows. Strips 3i and 32 of transite or other suitable electricalinsulating material are attached to the walls of the heatingcompartment, and spirally coiled wire of high electrical resistance isstrung between'the insulating strips. The wire is preferably arranged inthree sections 33, 34, and 35, each of which traverses substantially thewhole length and width of the heating compartment. This constructionresults in substantially uniform heating of the whole surface IS. Thethree sections of heater may be individually controlled by threeswitches 36, 31, and 38, respectively, which receive electrical powerthrough the attached cord 39. A rheostat may' be included in series withone or more of the heater sections to permit finer variation of theheating power between the fixed steps. I may also provide an adjustablethermostat, which may be of the bimetallic type, in metallic contactwith the surface l5 and including contacts which are in series with thesupply circuit from cord 39 in such a manner that the electric heatingcircuit is maintained accurately at the temperature for which thethermostat is set. A ruby light 45 is connected to be illuminatedwhenever any circuit is energized.

The space lying between the plate 30 and the bottom I4 is provided withshelves 40 and 4| which are adapted to hold squeegee tins such as 42 and43, respectively, which are not in .use.

The drier is operated as follows. The fabric 24 and its associatedtightening frame are lifted permitting the rod 2| to rest against theback wall l2 to hold the fabric tightening frame in the lifted position.Glossy finish prints to be dried are placed face down upon a chromiumplated squeegee tin 44. The squeegee tin and prints are placed on themetal surface IS with the prints on top. The fabric tightening frame islowered with the fabric which forces the ordinarily flat squeegee tin totake the convex shape of the surface l5. The tightening frame is forceddown until the fabric 24 is taut over the whole upper surface of thedrier, forcing the prints into close contact with the squeegee tin andwith the fabric. The latch operates to maintain the tightening frame andits fabric in this position. Assuming the heat has not been turned on,the switches 36, 31, 38,

are operated to energize the heater. Either one,

two or three sections of the heater may be employed to maintain thetemperature at the desired value for the particular work at hand.Generally the drying is continued four or five minutes after the drierhas come to proper temperature. During drying the fabric 24 absorbs asubstantial quantity of water from the wet prints which increases theefficiency of drying. As drying proceeds, the moist fabric steams andshrinks somewhat increasing the tightness with which the prints arepressed. If drying is stopped at the proper stage, sufficient moisturewill be found to be retained by the prints, by virtue of contact withthe moist fabric, that the prints are flexible and not easily crackedb'ybending. Since the drying is uniform no specks or spots will be found onthe prints. Since the prints are held tightly against a smooth surfaceduring drying, no curling of the edges will be observed in the prints.When drying has been completed, the

aromas latch 25 is loosened and the fabric and tightening frame lifted.The squeegee tin is removed where upon the prints may readily be takenoff.

The procedure in drying dull finish prints is the same except that nosqueegee tin need be used, but the prints are placed directly on theconvex metal surface It with their faces up toward the fabric 24. Otherpapers such as photo'- stats, blueprints, etc., can obviously be driedin the same manner.

While I have shown and described one particular embodiment of myinvention, it is understood that various changes and modifications indesign and construction may be made without departing from the spirit ofthe invention and the scope of the appended claims.

What I claim and desire to secure by Letters Patent is:

1. A drier for photographic prints and the like comprising a main framesupporting a convex surface, means for heating said surface, atightening frame pivotally mounted on said main frame to pivot about anaxis parallel to said surface and located adjacent one edge thereof, afabric sheet adapted to overlie said surface, one end of said sheetbeing secured unyieldingly adjacent said edge and the other end of saidsheet being unyieldingly secured to said tightening frame, in suchmanner that lowering said tightening frame stretches said fabric sheettightly over said surface, and means to latch said tightening frame inthe lowered position.

2. A drier for photographic prints and the like comprising a main framesupporting a convex surface, means for heating said surface, atightening frame pivotally mounted on said main frame to pivot about anaxis parallel to said surface and located adjacent one edge thereof, afabric sheet adapted to overlie said surface, one end of said sheetbeing secured unyieldingly adjacent said edge and the other end of saidsheet being secured to said tightening frame adjacent the free endthereof, in such manner that lowering said tightening frame stretchessaid fabric sheet tightly over said surface, and a releasable ratchetand pawl latch interposed between the free end of said tightening frameand said main frame for retaining said tightening frame in its loweredposition.

3. A drier for photographic prints and the like comprising a main framesupporting a convex surface, means for heating said surface, atightening frame pivotally mounted on said main frame to pivot about anaxis parallel to said surface and located adjacent one side of said mainframe, said tightening frame having a portion adapted to abut said mainframe in the raised position of said tightening frame, a fabric sheetadapted to overlie said surface, one end of said sheet being securedunyieldingly adjacent said pivot axis and the other end of said sheetbeing unyieldingly secured to the free end of said tightening frame, andmeans to releasably latch said tightening frame in a lowered position,all in such manner that said tightening frame is retained by gravity inthe raised position with the entire convex surface of said drierunobstructed by said fabric sheet or said tightening frame and thatlowering of said tightening frame to the lowered position stretches saidsheet tightly over said surface.

ROBERT M. LYNN.

